JP2013008659A - Ion implanter, ion beam measuring device, and ion beam measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new ion beam measurement.SOLUTION: An ion beam measuring device 10 includes: a measurement beam source 20 for emitting a measurement beam 12 which generates interaction between the measurement beam 12 and an ion beam 14; and a measurement beam detector 22 for detecting the measurement beam 12 which is emitted from the measurement beam source 20 and irradiated with the ion beam 14. The ion beam measuring device 10 can be applied to, for example, an ion implanter. The ion beam measuring device 10 may be a beam monitor which provides output related to the ion beam to a control system of the ion implanter.

Description

  The present invention relates to an ion beam measurement apparatus, an ion beam measurement method, and an ion beam irradiation apparatus, for example, an ion implantation apparatus, to which the ion beam measurement method can be applied.

  2. Description of the Related Art There is known an ion implantation apparatus for performing ion implantation by irradiating an object to be processed, for example, an ion beam containing ion species to be implanted into a semiconductor substrate. In general, an ion implantation apparatus is provided with a measuring instrument, such as a Faraday cup, for directly receiving an ion beam and performing beam measurement.

JP 2008-262748 A JP 2000-111942 A JP-A-7-153416

  In so-called contact-type beam measurement in which such an ion beam is directly received, the measuring device occupies the beam during the measurement, and thus the workpiece cannot be irradiated with the ion beam during the measurement. Similarly, measurement cannot be performed when the workpiece is irradiated with an ion beam. Therefore, there is a trade-off relationship between increasing the throughput of the irradiation process on the object to be processed and ensuring the beam quality by the high frequency measurement of the ion beam. In addition to the original purpose of irradiating the irradiated object, extra ionic material is consumed for measurement.

  One of the exemplary purposes of an aspect of the present invention is to provide a non-contact measurement that enables measurement while irradiating an object with an ion beam, or ion beam irradiation to which such measurement is applied. An object of the present invention is to provide an ion implantation apparatus.

  One embodiment of the present invention is an ion implantation apparatus. This apparatus irradiates the ion beam with a control system for controlling ion implantation processing by an ion beam to the object to be processed, and a measurement beam that causes an interaction between the ion beam and the ion beam. And a beam monitor that provides an output associated with the ion beam to the control system by detecting the measured beam.

  Another aspect of the present invention is an ion beam measurement apparatus. The apparatus includes a measurement beam source for emitting a measurement beam that interacts with the ion beam, and a measurement beam detector for detecting the measurement beam emitted from the measurement beam source and applied to the ion beam. .

  Another aspect of the present invention is an ion beam measurement method. The method includes irradiating the ion beam with a measurement beam that interacts with the ion beam, and detecting the measurement beam irradiated to the ion beam.

  Note that any combination of the above-described constituent elements and the constituent elements and expressions of the present invention replaced with each other among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to the present invention, non-contact ion beam measurement is provided.

It is a figure showing typically an example of 1 composition of an ion beam measuring device concerning a 1st embodiment of the present invention. It is a figure which shows the 1st modification of the ion beam measuring device which concerns on 1st Embodiment. It is a figure which shows the 2nd modification of the ion beam measuring device which concerns on 1st Embodiment. It is a figure which shows the 3rd modification of the ion beam measuring device which concerns on 1st Embodiment. It is a figure which shows the 4th modification of the ion beam measuring device which concerns on 1st Embodiment. It is a figure which shows the 4th modification of the ion beam measuring device which concerns on 1st Embodiment. It is a figure which shows the 5th modification of the ion beam measuring device which concerns on 1st Embodiment. It is a figure which shows the 5th modification of the ion beam measuring device which concerns on 1st Embodiment. It is a figure which shows schematically the whole structure of the ion implantation apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the process chamber of the ion implantation apparatus which concerns on 2nd Embodiment. It is a figure which shows the modification of the beam monitor which concerns on 2nd Embodiment. It is a figure for demonstrating one Example of the scanning sequence which concerns on 2nd Embodiment. It is a figure which shows an example of the protection apparatus for the optical elements relevant to the ion beam measuring device which concerns on one Embodiment of this invention. It is a figure which shows another example of the protection apparatus for the optical elements relevant to the ion beam measuring device which concerns on one Embodiment of this invention.

  FIG. 1 is a diagram schematically illustrating a configuration example of an ion beam measurement apparatus 10 according to the first embodiment of the present invention. Unlike a contact-type measuring instrument having a detection surface that directly receives an ion beam, the ion beam measurement apparatus 10 provides non-contact ion beam measurement by irradiating the ion beam 14 with the measurement beam 12. In other words, the ion beam measurement apparatus 10 indirectly measures the ion beam 14 by detecting the measurement beam 12 on which the ion beam 14 has acted. The detector that receives the irradiation of the ion beam 14 itself is not an essential component of the ion beam measurement apparatus 10. The measurement principle will be described with reference to FIG.

  The ion beam measurement apparatus 10 is configured to be incorporated as a subsystem for measuring the ion beam 14 in an ion beam irradiation system (for example, an ion implantation apparatus or a particle beam therapy apparatus) for irradiating the ion beam 14. Also good. Alternatively, the ion beam measurement apparatus 10 may be configured as a stand-alone measurement apparatus that is a stand-alone type.

  For convenience of explanation in FIG. 1 and each drawing referred to below, the traveling direction of the ion beam 14 is defined as the z direction, and the plane perpendicular to the z direction is defined as the xy plane. As will be described later, when the ion beam 14 is scanned with respect to the workpiece 16, the scanning direction is defined as the y direction, and the z direction and the direction perpendicular to the y direction are defined as the x direction. The scanning plane (for example, yz plane) of the ion beam 14 is defined by the locus drawn by the central axis of the ion beam 14 when the ion beam 14 is scanned. Since the ion beam 14 actually has a beam cross section of a certain size, the ion beam is also irradiated to a position away from the scanning plane in the size range up and down (for example, the x direction). Taking this into consideration, it can be said that the passage region of the ion beam 14 by scanning is a three-dimensional region extending up and down the scanning plane.

  The ion beam 14 is guided to the processing chamber 18 for irradiation of the workpiece 16. In one embodiment, the workpiece 16 is continuously irradiated with the ion beam 14. That is, the ion beam 14 is continuously generated for a desired irradiation period according to a desired target profile (for example, target beam current) by an ion beam generation unit (not shown), and is irradiated on the object 16 to be processed. In another embodiment, the ion beam 14 may be a pulsed ion beam.

  In an embodiment in which the ion beam measuring apparatus 10 is applied to an ion implantation apparatus, the workpiece 16 is a semiconductor substrate (for example, a silicon wafer), and is movable or stationary with respect to the ion beam 14 in the xy plane. It is supported and accommodated in the processing chamber 18. For the ion beam processing, the processing chamber 18 is maintained in a desired vacuum state, and a vacuum exhaust device (for example, a cryopump or other vacuum pump (not shown)) for that purpose is attached. The processing chamber 18 is also called a vacuum chamber or a process chamber, for example. In the case of an ion implantation apparatus, the processing chamber 18 is sometimes called an end station, and the workpiece 16 is sometimes called a target.

  The processing chamber 18 does not necessarily contain the object to be processed 16, and the processing chamber 18 is configured as an irradiation chamber or a measurement chamber for irradiating the measurement beam 12 to the ion beam 14 to be incident on the processing object 16. May be. In that case, the workpiece 16 is disposed downstream of the processing chamber 18 along the path of the ion beam 14, and the ion beam 14 that has entered the processing chamber 18 exits the processing chamber 18 via the measurement beam 12, and You may inject into the processed material 16. FIG.

  The ion beam measurement apparatus 10 includes a measurement beam source 20 for emitting a measurement beam 12. The measurement beam 12 is an electromagnetic wave having a wavelength or wavelength range that causes an interaction with the ion beam 14. The interaction between the ion beam 14 and the measurement beam 12 includes at least one of absorption, diffraction, scattering, reflection, and transmission of the measurement beam 12 by the ion beam 14. The electromagnetic wave for measurement used in the ion beam measurement apparatus 10 does not necessarily have to be a beam, that is, radiation having directivity, and the ion beam measurement apparatus 10 generates an interaction with the ion beam 14. You may provide the radiation source which radiates | emits the electromagnetic wave which has a wavelength or a wavelength range.

  In one embodiment, in order to increase the interaction caused by the ion beam 14 on the measurement beam 12, the ion beam 14 of the beam spot of the measurement beam 12 (that is, a beam cross section by a plane perpendicular to the traveling direction of the measurement beam 12) Increase the ratio of the area irradiated to. The spot diameter of the measurement beam 12 is preferably made smaller than the size of the ion beam 14 so that the entire beam spot of the measurement beam 12 is irradiated on the ion beam 14. In this case, the measurement beam 12 is included in the ion beam 14 at the irradiation position 34 of the measurement beam 12 to the ion beam 14.

  On the other hand, when the beam spot of the measurement beam 12 has a small diameter, depending on the irradiation position accuracy of the ion beam 14 (for example, in the x direction in FIG. 1), the irradiation position may be shifted and the ion beam 14 may deviate from the measurement beam 12. is assumed. Therefore, in one embodiment, conversely, the ion beam 14 is included in the measurement beam 12 at the irradiation position 34 of the measurement beam 12 to the ion beam 14 by making the spot diameter of the measurement beam 12 larger than the dimension of the ion beam 14. You may be made to do. In this way, even if some misalignment occurs at the irradiation position of the ion beam 14, the crossing state (that is, beam measurement) between the ion beam 14 and the measurement beam 12 can be easily continued.

  The ion beam measurement apparatus 10 includes a measurement beam detector 22 for detecting the measurement beam 12. The measurement beam detector 22 is provided for detecting the measurement beam 12 emitted from the measurement beam source 20 and irradiated on the ion beam 14. The measurement beam detector 22 is configured to receive the measurement beam 12 on its detection surface and output a detection signal S1. In one embodiment, measurement beam detector 22 includes a light receiving surface or receiver for receiving or receiving measurement beam 12. The measurement beam detector 22 generates a detection signal S1 related to, for example, the intensity of the received or received measurement beam 12.

  In one embodiment, the measurement beam source 20 and the measurement beam detector 22 are arranged such that the measurement beam 12 is emitted from the measurement beam source 20 and intersects the ion beam 14 and enters the measurement beam detector 22. . For example, the measurement beam source 20 and the measurement beam detector 22 may be ion beams so that the measurement beam 12 takes a linear beam path from the measurement beam source 20 through the ion beam 14 to the measurement beam detector 22. The 14 incident paths may be arranged to face each other. Alternatively, as will be described later, the ion beam measurement apparatus 10 may include a beam optical system 24 for transmitting the measurement beam 12 from the measurement beam source 20 to the measurement beam detector 22.

  As shown, the measurement beam 12 may be irradiated perpendicularly to the ion beam 14 or may be irradiated so as to cross obliquely. In the case of orthogonal irradiation, the ion beam measuring device 10 can be arranged relatively compactly in the traveling direction of the ion beam 14, and in the case of oblique irradiation, the measurement beam 12 intersects the ion beam 14. This is preferable in that the length can be increased.

  In one embodiment, in order to irradiate the ion beam 14 in a wider range than the beam spot of the ion beam 14, for example, the entire surface of the workpiece 16 or a desired ion beam irradiation region, the ion beam 14 is at least in one direction. It may be scanned. An ion beam scanning control unit (not shown) may be provided for scanning the ion beam 14. For example, as indicated by an arrow 28 in FIG. 1, the ion beam 14 may be reciprocated in the y direction. Note that the workpiece 16 may be moved with respect to the ion beam 14 while scanning the ion beam 14 or instead of the scanning.

  In an embodiment in which the ion beam 14 is scanned, the measurement beam 12 has a scanning plane (yz) determined by the scanning direction of the ion beam 14 (y direction in FIG. 1) and the traveling direction of the ion beam 14 (z direction). The ion beam 14 is preferably irradiated along the surface. It is not always required that the irradiation direction of the measurement beam 12 be accurately along the scanning plane. Usually, it is sufficient if the path of the measurement beam 12 is determined so as to traverse the passing region of the ion beam 14 by scanning. In this way, the ion beam 14 can be irradiated with the measurement beam 12 when the ion beam 14 is in any scanning position (that is, over the entire scanning range). That is, the ion beam 14 can be continuously measured during the scanning movement of the ion beam 14.

  The ion beam measurement apparatus 10 may include an arithmetic processing unit 26 for giving a measurement result based on an input signal including the detection signal S1. The arithmetic processing unit 26 may be provided separately from the measurement beam detector 22 so as to be able to receive the detection signal S1 from the measurement beam detector 22, and may be a calculation device such as a known personal computer. Alternatively, the arithmetic processing unit 26 may be integrally mounted on the measurement beam detector 22.

  For example, the arithmetic processing unit 26 may calculate the absolute value of the ion beam amount (for example, the beam current or the implantation dose amount) based on the detection signal S1. The arithmetic processing unit 26 may calculate a relative change amount with respect to a reference of the ion beam amount based on the detection signal S1. For example, the arithmetic processing unit 26 may obtain the ion beam amount by referring to a map representing the relationship between the ion beam amount stored in advance and the detection signal S1. The arithmetic processing unit 26 may determine whether or not the detection signal S1 or a value calculated from the detection signal S1 is included in a predetermined allowable range. If it is determined that it is outside the allowable range, the arithmetic processing unit 26 may store the determination result or output a warning.

  In a preferred embodiment, the measurement beam source 20 is a laser light source and the measurement beam detector 22 is a detector (eg, a photodiode) that can detect the laser light. In this case, the interaction between the ion beam 14 and the measurement beam 12 is absorption, diffraction, reflection, or scattering of the measurement beam 12 by the ion beam 14. When the measurement beam 12 is absorbed, diffracted, reflected, or scattered at the irradiation position of the ion beam 14, the intensity of the ion beam 14 decreases. The intensity of the measurement beam 12 that has passed through the ion beam 14 is lower than immediately after it exits the measurement beam source 20. The measurement beam detector 22 outputs a detection signal S1 corresponding to the intensity of the received measurement beam 12. This decrease in intensity of the measurement beam 12 correlates with the ion density of the ion beam 14. Therefore, non-contact measurement of the ion beam 14 becomes possible by detecting the measurement beam 12. The ion beam 14 can be measured without receiving the ion beam 14 with a physical detection element.

  In a more preferred embodiment, the laser light source used as the measurement beam source 20 is a laser that emits laser light having a wavelength that matches the absorption wavelength of the ion species contained in the ion beam 14 or a wavelength region that includes the absorption wavelength. Light source. In other words, the laser light source is selected so that the light energy of the laser light determined according to the wavelength becomes equal to the absorption energy of the ion species of the ion beam 14. At this time, the interaction between the ion beam 14 and the measurement beam 12 is dominated by the absorption of the measurement beam 12 by the ion beam 14. In this way, the difference in intensity of the measurement beam 12 before and after irradiation with the ion beam 14 can be made relatively large, and the measurement accuracy of the ion beam measurement apparatus 10 can be increased.

  Note that the wavelength of the laser beam does not necessarily exactly match the absorption wavelength of the ion species of the ion beam 14, and a certain amount of deviation is allowed in practice. In order to give absorption energy to a typical ion beam 14 when the ion beam measuring apparatus 10 is applied to an ion implantation apparatus, a light source used in, for example, atomic absorption spectrometry as the measurement beam source 20 is desirable.

  Moreover, in the aspect which measures the intensity | strength change of the measurement beam 12 by the diffraction of the measurement beam 12 by the ion beam 14, reflection, or scattering, the preferable wavelength of the ion beam 14 is not necessarily restricted to a specific wavelength or a specific narrow band. In this case, the measurement beam 12 may have an arbitrarily selected wavelength or wavelength range.

  In one embodiment, it is preferable to add a reference beam 30 that is not irradiated to the ion beam 14 in order to generate a reference signal S2 as a reference. For this purpose, the ion beam measurement apparatus 10 may further include a reference beam source for emitting the reference beam 30 and a reference beam detector for detecting the reference beam 30. The reference beam source and the reference beam detector may have the same configuration as the measurement beam source 20 and the measurement beam detector 22, respectively.

  Reference beam 30 may be emitted from the same source as measurement beam 12, ie, measurement beam source 20. A beam emitted from a beam source (for example, a laser light source) may actually vary somewhat in time even if it is possible to emit a uniform intensity according to specifications. For example, the beam intensity can fluctuate in a very short time, or the beam intensity can change over the long term. Therefore, by comparing the measurement beam 12 with the reference beam 30 that is emitted from the same source as the measurement beam 12 and does not pass through the ion beam 14, the influence on the measurement due to the fluctuation of the beam intensity or the change over time can be reduced or compensated. Can do.

  In one embodiment shown in FIG. 1, the beam optics 24 includes a beam splitter 32 for splitting the reference beam 30 from the measurement beam 12 emitted from the measurement beam source 20. The beam splitter 32 is provided between the measurement beam source 20 and the ion beam irradiation position 34 of the measurement beam 12 in the path of the measurement beam 12. For example, the measurement beam source 20 receives the outgoing beam of the measurement beam source 20 directly. It is arranged to face. A part of the outgoing beam of the measurement beam source 20 is reflected (or transmitted) as the measurement beam 12 by the beam splitter 32, and the rest is transmitted (or reflected) by the beam splitter 32 as the reference beam 30.

  The beam splitter 32 is, for example, a half mirror, in which case the measurement beam 12 and the reference beam 30 have the same intensity. In the example shown in the figure, half of the beam emitted from the measurement beam source 20 in the y direction goes straight through the half mirror as the reference beam 30 in the y direction, and the other half is bent as the measurement beam 12 in the z direction by the half mirror. It is done. Alternatively, calibration is performed by the measurement beam detector 22 or the arithmetic processing unit 26 so that the signals are equal between the measurement beam 12 and the reference beam 30 before the ion beam 14 is irradiated.

  The beam optical system 24 includes a first bending mirror 36 for bending and reflecting the incident beam by 90 degrees. The first bending mirror 36 is disposed to face the beam splitter 32 so as to reflect the measurement beam 12 bent in the z direction by the beam splitter 32 in the y direction again. The measurement beam 12 reflected by the first bending mirror 36 travels straight on the ion beam irradiation side of the workpiece 16 and enters the measurement beam detector 22 via the ion beam 14.

  The beam optical system 24 further includes a second bending mirror 38 and a third bending mirror 40 for bending and reflecting the incident beam by 90 degrees. The reference beam 30 travels on the non-irradiated side of the workpiece 16 in order to bypass the ion beam 14. The second bending mirror 38 is disposed so as to face the beam splitter 32 so as to reflect the reference beam 30 straightly traveling in the y direction through the beam splitter 32 in the z direction. The third folding mirror 40 is disposed so as to face the second folding mirror 38 so as to reflect the reference beam 30 folded in the z direction by the second folding mirror 38 again in the y direction. The reference beam 30 reflected by the third bending mirror 40 is incident on the measurement beam detector 22.

  In this way, the beam optical system 24 provides a substantially rectangular beam path surrounding the workpiece 16, and the measurement beam source 20 and the measurement beam detector 22 are disposed on the diagonal of the rectangle. Gas molecules exist in the processing chamber 18 at a density corresponding to the degree of vacuum. The measuring beam 12 is also affected by such gas molecules, for example the intensity is reduced. The beam optics 24 causes the measurement beam 12 and the reference beam 30 to reach the detector via a beam path that is a substantially equal distance from the beam source. Therefore, by using the reference beam 30 as a reference, it is possible to reduce or compensate for the influence on the measurement of the gas existing in the vacuum.

  It should be noted that the configuration of the illustrated beam optical system 24 for matching the path lengths of the measurement beam 12 and the reference beam 30 is merely an example, and various configurations are possible. If it can be estimated that the influence of the gas on the measurement beam 12 is sufficiently small, the path lengths of the measurement beam 12 and the reference beam 30 may be different. Further, when a beam source capable of emitting a beam with sufficiently uniform intensity can be adopted, the reference beam source may be a beam source separate from the measurement beam source 20.

  The reference beam detector is configured to receive a reference beam 30 and output a reference signal S2 related to the intensity of the reference beam 30, for example. In the example shown, the reference beam detector is integrated in the measurement beam detector 22. The measurement beam detector 22 includes at least two input / output systems, one of which receives the measurement beam 12 and outputs the detection signal S1, and the other one receives the reference beam 30 and receives the reference signal S2. Output. In another embodiment, the measurement beam source 20 has, for example, an intensity detection function of the beam, or the measurement beam source 20 may include a beam detector in or near the measurement beam source 20 or The beam detector may output the detection signal as a reference signal S2.

  The arithmetic processing unit 26 is connected to the reference beam detector so as to be able to receive the reference signal S2, and may calculate the ion beam amount based on the detection signal S1 and the reference signal S2. The arithmetic processing unit 26 may determine whether or not the ion beam amount has changed by comparing the detection signal S1 with the reference signal S2. For example, the arithmetic processing unit 26 may calculate a difference between the detection signal S1 and the reference signal S2 or a ratio between the detection signal S1 and the reference signal S2. The signal difference S1-S2 or the signal ratio S1 / S2 obtained in this way provides a relative indicator for the amount of ion beam. The arithmetic processing unit 26 may determine whether or not the calculation result is included in a predetermined allowable range. If it is determined that it is outside the allowable range, the arithmetic processing unit 26 may output a warning.

  In an embodiment in which the ion beam 14 is scanned, the arithmetic processing unit 26 receives scanning position information indicating the scanning position of the ion beam 14 from an ion beam scanning control unit (not shown) for scanning the ion beam 14. It may be configured to receive input. The arithmetic processing unit 26 may specify the ion beam scanning position from which the detection signal S1 is obtained by associating the ion beam scanning position information at a certain time with the detection signal S1 at that time. In this way, the scanning position where the ion beam 14 has changed can be obtained.

  The operation of the ion beam measuring apparatus 10 will be described. The measurement beam 12 emitted from the measurement beam source 20 is guided to the ion beam irradiation position 34 by the beam optical system 24. The measurement beam 12 irradiated to the ion beam 14 enters the measurement beam detector 22. The measurement beam detector 22 receives the measurement beam 12 and generates a detection signal S 1 and outputs the detection signal S 1 to the arithmetic processing unit 26.

  The intensity of the measurement beam 12 is reduced mainly by the action of the ion beam 14. The intensity of the measurement beam 12 is also affected by factors associated with the measurement system, such as the stability of the beam radiation of the measurement beam source 20 and the presence of gas in the processing chamber 18. When there is a sufficiently strong ion beam 14 at the ion beam irradiation position 34, it is possible to obtain a detection signal S1 representing an intensity decrease exceeding the beam intensity decrease due to such incidental factors. Thresholds that exceed ion beam intensity degradation due to incidental factors can be predetermined experimentally or empirically. Therefore, by comparing the threshold value with the detection signal S1, it is possible to determine whether or not the beam intensity has decreased. The intensity of the ion beam 14 is clearly reduced, for example, when the ion beam 14 is accidentally blinked or extinguished. Therefore, at least accidental blinking or disappearance of the ion beam 14 can be captured.

  A reference beam 30 is also emitted from the measurement beam source 20 and enters the measurement beam detector 22 via an optical path substantially equidistant from the measurement beam 12. The measurement beam detector 22 receives the reference beam 30 and generates a reference signal S 2 and outputs it to the arithmetic processing unit 26. It can be evaluated that the reference beam 30 is affected by the above-mentioned incidental factors in the same manner as the measurement beam 12. Therefore, by using the reference signal S2, it is possible to remove the influence of incidental factors from the detection signal S1.

  In this way, according to the ion beam measurement apparatus 10 according to the first embodiment, the ion beam 14 is processed by using measurement radiation (for example, electromagnetic waves or light) that interacts with the ion beam 14. It is possible to measure without contact while irradiating the object 16. In one embodiment, the measurement radiation is a measurement beam. In one embodiment, the measurement radiation is a beam of electromagnetic waves.

  By the way, regarding the pulsed ion beam, for example, another method of detecting the ion beam in a non-contact manner from a magnetic field change around the ion beam caused by the pulse can be considered. However, such detection is not necessarily suitable for a continuously emitted ion beam, since the magnetic field can be stationary. The measurement by the ion beam measurement apparatus 10 is particularly preferable in that it can be applied not only to the pulse ion beam but also to the continuous ion beam 14.

  FIG. 2 is a diagram illustrating a first modification example of the ion beam measurement apparatus 10. In the example shown in FIG. 1, the reference beam 30 is detoured to the non-irradiated side of the workpiece 16, whereas in FIG. 2, the paths of the measurement beam 12 and the reference beam 30 are the ions of the workpiece 16. A configuration example taken on the beam irradiation side is shown. Note that FIG. 1 shows the yz plane, whereas FIG. 2 shows the xy plane.

  FIG. 2 shows an ion beam irradiation area 42 to the workpiece 16. The ion beam irradiation area 42 indicates, for example, a scanning range of the ion beam 14 (see FIG. 1). Alternatively, the ion beam irradiation area 42 may be a ribbon-like ion beam (also referred to as a long beam) having a beam cross section extending in the longitudinal direction (y direction in FIG. 2). The workpiece 16 is, for example, a circular substrate, and its outline is illustrated by a broken line. The object to be processed 16 is not limited to a circular substrate, but may be another shape such as a rectangular substrate, or may not necessarily be a plate-shaped member, and may be an ion beam irradiation target having an arbitrary three-dimensional shape. Good.

  In the following, for comparison with the ribbon beam, the normal ion beam 14 may be referred to as a spot beam, but this only means that the beam cross section is spot-like in comparison with the ribbon beam. It is not limited that the ion beam 14 has a specific beam cross-sectional shape.

  In this modification, the measurement beam 12 is irradiated to the ion beam on the ion beam surface determined by the ion beam irradiation area 42 and the z direction which is the ion beam traveling direction. The ion beam surface is a beam irradiation region having a thickness corresponding to the beam diameter of the spot beam. On the other hand, the reference beam 30 detours outside the ion beam surface on the ion beam irradiation side of the workpiece 16. As shown, the measurement beam 12 emitted from the measurement beam source 20 is linearly incident on the measurement beam detector 22 via the beam splitter and ion beam irradiation area 42 of the beam optical system 24. The reference beam 30 emitted from the measurement beam source 20 and branched by the beam splitter of the beam optical system 24 is reflected by the mirror of the beam optical system 24 and enters the measurement beam detector 22. In this way, the reference beam 30 can be supplied from the same source as the measurement beam 12, and the measurement beam 12 and the reference beam 30 can reach the detector via a substantially equal distance.

  Further, as shown in the drawing, the dimension in the longitudinal direction of the ion beam irradiation area 42 can be accommodated in the width of the workpiece 16 in that direction. For example, in a typical ion implantation apparatus, a contact type detector (for example, a Faraday cup) is provided on one side or both sides of the workpiece 16, and it is practically essential to irradiate the contact type detector with an ion beam. Has been. Therefore, the ion beam irradiation area needs to be longer than the width of the workpiece 16. However, according to one embodiment of the present invention, the ion beam irradiation area 42 can be made smaller in accordance with the region to be irradiated of the workpiece 16 without being subjected to such restrictions. Thus, according to an embodiment of the present invention, an improvement in throughput and a reduction in consumption of ionic materials are realized.

  FIG. 3 is a diagram illustrating a second modification example of the ion beam measurement apparatus 10. In the above-described embodiment, the measurement beam source 20 and the measurement beam detector 22 are arranged to face each other across the incident path of the ion beam 14, but the embodiment of the present invention is not limited to this. The measurement beam source 20 and the measurement beam detector 22 may be arranged, for example, adjacent to each other on the same side with respect to the ion beam 14. Further, the irradiation position of the measurement beam 12 to the ion beam 14 is not limited to one place, and may be a plurality of places.

  As shown in FIG. 3, the beam optical system 24 includes a folding mirror for reflecting the incident beam in the direction opposite to the incident direction. The measurement beam 12 emitted from the measurement beam source 20 passes through the ion beam 14 and enters the folding mirror of the beam optical system 24. The measurement beam 12 is directed in the opposite direction due to reflection by the folding mirror and passes through the ion beam 14 again. In this way, the measurement beam 12 is incident on the measurement beam detector 22. Similarly, by making the path of the measurement beam 12 meander, the number of times the measurement beam 12 intersects the ion beam 14 can be further increased. By increasing the number of times the measurement beam 12 intersects the ion beam 14, the effect that the measurement beam 12 receives from the ion beam 14 can be strengthened.

  Although it is not essential in the present invention to apply the reference beam as described above, when the reference beam is added to the second modification, for example, the ion beam surface (for example, as in the first modification described above) The path of the reference beam may be defined outside the plane (yz plane). The path of the reference beam can be, for example, a path that meanders in a parallel plane that is a distance Δx away from the ion beam plane in the x direction, like the measurement beam 12. In order to separate the reference beam from the measurement beam 12, the distance Δx is preferably a distance corresponding to the ion beam diameter, for example.

  FIG. 4 is a diagram illustrating a third modification example of the ion beam measurement apparatus 10. At least one of the measurement beam source 20 and the measurement beam detector 22 may be provided outside the irradiation chamber or the processing chamber 18. At least one of the measurement beam source 20 and the measurement beam detector 22 provided outside may be connected to the irradiation chamber or the processing chamber 18 by a light guide member 44 for transmitting the measurement beam 12. Similarly, at least one of the reference beam source and the reference beam detector may be provided outside the irradiation chamber or the processing chamber 18 via a light guide member 44 for transmitting the reference beam 30. The light guide member 44 includes, for example, a light receiving portion (for example, a window portion) provided on the wall surface of the irradiation chamber or the processing chamber 18 or in the vicinity thereof, and an optical fiber for guiding the beam received by the light receiving portion to the detector. You may prepare.

  In the embodiment shown in FIG. 4, the measurement beam detector 22 and the reference beam detector 46 are provided outside the processing chamber 18. The measurement beam detector 22 and the reference beam detector 46 may be separate detectors. Thus, by arranging the beam detector outside the processing chamber 18 and away from the ion beam 14, it is expected that noise that may occur in the detection signal S1 and the reference signal S2 is reduced. The reference beam 30 detours outside the ion beam surface, for example, as in the first modification shown in FIG. 2, and this is schematically indicated by a broken line.

  The ion beam measurement apparatus 10 further includes a contact-type measuring instrument that receives an ion beam 14 and measures the ion beam, for example, a Faraday cup 48 that outputs a beam current signal S3 representing the beam current of the ion beam 14. Also good. For example, the Faraday cup 48 is disposed on one side or both sides of the workpiece 16. The beam current signal S3 output from the Faraday cup 48 may be input to the arithmetic processing unit 26 in the same manner as the detection signal S1 and the reference signal S2, for example. For this purpose, the ion beam 14 may be scanned onto the detection surface of the Faraday cup 48. Contact-type instruments (eg, Faraday cup 48) may be applied to other embodiments described herein.

  The arithmetic processing unit 26 may calibrate the measurement result based on the detection signal S1 and the reference signal S2 using the beam current signal S3. The calibration process may include, for example, associating the beam current signal S3 with the detection signal S1 and the reference signal S2 in advance over a certain beam current range. The arithmetic processing unit 26 may obtain the beam current of the ion beam 14 from the detection signal S1 and the reference signal S2 using the relationship. In this case, since the calibration process can be performed using the beam current signal S3, the reference beam 30 and the reference signal S2 may be omitted.

  5 and 6 are diagrams showing a fourth modification example of the ion beam measuring apparatus 10. When the ion beam 14 is in a plasma state, the ion beam 14 has a specific plasma frequency corresponding to its electron density. At this time, the ion beam 14 absorbs, refracts, reflects, or transmits the irradiated electromagnetic wave by the same phenomenon as the radio wave reflection by the ionosphere. For example, when the frequency of the irradiated electromagnetic wave is lower than the plasma frequency of the ion beam 14, at least a part of the electromagnetic wave is reflected by the ion beam 14, and conversely, when the frequency of the electromagnetic wave is higher than the plasma frequency of the ion beam 14. At least a part of the electromagnetic wave can pass through the ion beam 14.

  Therefore, the measurement beam source 20 may be an electromagnetic wave source that emits an electromagnetic wave having directivity that reflects or transmits according to the plasma frequency of the ion beam 14, for example, a millimeter wave source or a microwave source. The measurement beam detector 22 may be a receiver for receiving electromagnetic waves emitted from the measurement beam source 20. As shown in FIGS. 5 and 6, such a receiver is disposed at at least one of a position where the measurement beam 12 reflects and reaches the ion beam 14 and a position where the measurement beam 12 reaches the ion beam 14. An appropriate optical system or repeater may be provided between the transmission source as the measurement beam source 20 and the receiver as the measurement beam detector 22. A reference beam system may be added in the same manner as in the above-described embodiment.

  FIG. 5 shows a state where the measurement beam 12 is transmitted through the ion beam 14, and FIG. 6 shows a state where the measurement beam 12 is reflected by the ion beam 14. In this case, the interaction between the ion beam 14 and the measurement beam 12 is mainly the reflection or transmission of the measurement beam 12 by the ion beam 14. The frequency of the measurement beam 12 is set to a plasma frequency corresponding to a desired current density of the ion beam 14. This beam current density is selected from, for example, a range that is effective and allowable for irradiation of the workpiece 16, and is set to a lower limit value of the allowable range, for example. The frequency of the measurement beam 12 is selected from a range of 10 MHz to 10 GHz, for example. The incident angle of the measurement beam 12 on the ion beam 14 is preferably determined so that the ion beam 14 causes total reflection of the measurement beam 12.

  As shown in FIG. 5, the measurement beam 12 emitted from the measurement beam source 20 is incident on the ion beam 14 obliquely, for example. When the plasma frequency corresponding to the current density of the ion beam 14 is smaller than the frequency of the measurement beam 12, the measurement beam 12 reaches the measurement beam detector 22 as shown. The measurement beam detector 22 outputs a detection signal S 1 corresponding to the reception intensity of the measurement beam 12.

  As shown in FIG. 6, when the plasma frequency corresponding to the current density of the ion beam 14 is higher than the frequency of the measurement beam 12, the measurement beam 12 is reflected by the ion beam 14. At least some or all of the measurement beam 12 does not reach the measurement beam detector 22. Therefore, the detection signal S1 output from the measurement beam detector 22 is greatly reduced compared to the state of FIG. Thus, it can be detected based on the detection signal S1 whether or not the ion beam 14 having an effective intensity is irradiated. Note that, as indicated by a broken line in FIG. 6, the measurement beam detector 22 may be disposed at a position for receiving the reflected ion beam 14.

  The ion beam measurement apparatus 10 may include a plasma shower 50. The plasma shower 50 may be provided upstream of the ion beam irradiation position 34 of the measurement beam 12 in the beam line of the ion beam 14. The plasma shower 50 is a known component that supplies low energy electrons to the ion beam 14 in order to neutralize the electric field due to the ions of the ion beam 14. By providing the plasma shower 50, it is possible to ensure that the ion beam 14 is in a plasma state.

  7 and 8 are diagrams showing a fifth modification example of the ion beam measuring apparatus 10. The ion beam measurement apparatus 10 may include a plurality of measurement beam detectors along the beam line of the ion beam 14. In other words, the measurement beam source 20 may irradiate the measurement beam to a plurality of positions along the traveling direction of the ion beam 14. For this purpose, the ion beam measurement apparatus 10 may include a plurality of measurement beam sources 20. The ion beam measurement apparatus 10 may measure the transport efficiency of the ion beam 14 from the detection results of a plurality of measurement beam detectors. The measurement beam detector may be the measurement beam detector 22 described in connection with the previously described embodiment (see, for example, FIG. 1).

  In one embodiment shown in FIG. 7, a common beam emitted from a single measurement beam source 20 is split by the beam optics 24 into a reference beam 30, a first measurement beam 52, and a second measurement beam 54. The The reference beam 30 bypasses the ion beam 14, and the first measurement beam 52 and the second measurement beam 54 are irradiated on the ion beam 14. The first measurement beam 52 is applied to the ion beam 14 on the downstream side of the second measurement beam 54.

  The first measurement beam 52 and the second measurement beam 54 irradiated to the ion beam 14 are detected by a first beam detector 56 and a second beam detector 58, respectively. The reference beam 30 is detected by a reference beam detector 46. The first beam detector 56 and the second beam detector 58 output a first detection signal S1-1 and a second detection signal S1-2, respectively. The reference beam detector 46 outputs a reference signal S2. The first detection signal S1-1, the second detection signal S1-2, and the reference signal S2 are input to the arithmetic processing unit 26. The arithmetic processing unit 26 calculates the measurement result based on the input signal and outputs it as necessary.

  In the embodiment shown in FIG. 8, a plurality of sets of measurement beams and reference beams are provided along the beam line 60 of the ion beam 14. The ion beam measurement apparatus 10 includes a first beam source 66 for providing a first measurement beam 52 and a first reference beam 62, and a first beam detector 56 for receiving the first measurement beam 52 and the first reference beam 62. And comprising. The ion beam measurement apparatus 10 also includes a second beam source 68 for providing a second measurement beam 54 and a second reference beam 64, and a second beam detection for receiving the second measurement beam 54 and the second reference beam 64. Instrument 58.

  The first beam detector 56 outputs a first detection signal S1-1 and a first reference signal S2-1, and the second beam detector 58 outputs a second detection signal S1-2 and a second reference signal S2-2. To do. These output signals are input to the arithmetic processing unit 26, and the arithmetic processing unit 26 calculates the measurement result based on the input signal and outputs it as necessary.

  FIG. 9 is a diagram schematically showing an overall configuration of an ion implantation apparatus 100 according to the second embodiment of the present invention. FIG. 9 shows typical components included in the ion implantation apparatus 100. FIG. 10 is a view showing the processing chamber 112 of the ion implantation apparatus 100 according to the second embodiment. FIG. 10 shows a schematic configuration when the processing chamber 112 is viewed from the beam line assembly 110 in the beam incident direction.

  The ion implantation apparatus 100 is an apparatus for performing an ion implantation process in which an element is ionized to generate an ion beam 102 and irradiate the substrate (for example, a semiconductor substrate) 104 with the element. As in FIG. 1, for convenience of explanation, the incident direction of the ion beam 102 to the substrate 104 is defined as the z direction, and a plane perpendicular to the z direction is defined as an xy plane. The z direction indicates the global traveling direction of the ion beam 102 in the beam line. As will be described later, when the ion beam 102 is scanned with respect to the substrate 104, the scanning direction is defined as the y direction, and the z direction and the direction perpendicular to the y direction are defined as the x direction. In one embodiment, the yz plane is a horizontal plane and the x direction is a vertical direction.

  The ion implantation apparatus 100 includes a non-contact beam monitor 106 for providing a beam monitor output using the same measurement principle as the ion beam measurement apparatus 10 according to the first embodiment. Therefore, the beam monitor 106 may be any one of the various ion beam measurement apparatuses 10 according to the first embodiment and its modifications.

  The ion implantation apparatus 100 includes an ion source 108, a beam line assembly 110, and a processing chamber 112. The ion source 108 is configured to ionize an element to be implanted. The beam line assembly 110 transports, accelerates, and shapes the ion beam 102 with a mass analyzer 114 for selecting ions to be implanted into the substrate 104 out of ions ionized by the ion source 108 by mass. Or a beam transport system 116 for scanning. On the downstream side of the mass analyzer 114, a mass analysis slit 118 for passing the ion beam 102 made of ions having a predetermined mass to the beam transport system 116 is provided.

  The beam transport system 116 includes a beam scanner 120 for scanning the ion beam 102 in at least one direction (for example, the y direction). A scannable range in the y direction of the ion beam 102 by the beam scanner 120 is indicated by an arrow 138.

  The processing chamber 112 includes a beam monitor 106 for monitoring the ion beam 102. The beam monitor 106 monitors the ion beam 102 by causing the measurement beam 130 to act on the ion beam 102 and detecting the measurement beam 130. Beam monitor 106 provides a monitor output associated with ion beam 102 to control system 128. The beam monitor output includes a detection signal S1. The beam monitor 106 may provide a reference signal S2 based on the reference beam 132 to the control system 128. The beam monitor 106 includes a measurement beam source 134 for irradiating the ion beam 102 with the measurement beam 130, and a measurement beam detector 136 for detecting the measurement beam 130 irradiated on the ion beam 102.

  The beam monitor 106 may be provided in the beam line assembly 110. The ion implantation apparatus 100 may include a plurality of beam monitors 106 along the beam line.

  The processing chamber 112 may include a contact ion beam detector (for example, a Faraday cup) 122. The ion beam detector 122 may output a beam current signal S3 to the control system 128. It is not essential to provide such a contact type detector. The ion beam detector 122 is preferably disposed at a position adjacent to the substrate 104 in the ion beam scanning direction. The ion beam detector 122 may be arranged on one side (in the case of illustration) or both sides of the substrate 104. The ion beam detector 122 may be a detector that can be moved in and out of the beam line as necessary for measurement.

  The ion beam measurement system of the ion implantation apparatus 100 may further include an arbitrary measurement device in addition to the beam monitor 106 and the ion beam detector 122. The ion implantation apparatus 100 is a beam for interrupting the ion beam 102 in the middle of the beam line in accordance with a control command from the control system 128 or based on a measurement result of an ion beam measurement system including the beam monitor 106. A shutter (not shown) may be provided.

  Further, the processing chamber 112 includes a substrate support portion 124 for supporting the substrate 104. The substrate 104 is supported by the substrate support portion 124 and is accommodated in the processing chamber 112. The substrate support unit 124 is configured as a so-called mechanical scan system for moving the substrate 104 with respect to the ion beam 102, and includes a table or platen for holding the substrate 104, and a drive mechanism for moving the table or platen. ,including. The mechanical scanning system is configured to reciprocate the substrate 104 in a scanning range in a direction (x direction) perpendicular to the ion beam traveling direction (z direction) and the scanning direction (y direction), for example. Such a scanning method that combines a beam scan in one direction and a mechanical scan in the vertical direction is sometimes called a hybrid scan.

  As shown in FIG. 10, the substrate 104 is irradiated with an ion beam 102 having a spot-like cross section. As described above, the ion beam 102 is scanned in the y direction, and the substrate 104 is mechanically scanned in the x direction. Ion beam detectors 122 are provided on both sides of the substrate 104 in the scanning range 138 of the ion beam 102. Measurement of the ion beam detector 122 is limited to the ion beam 102 scanned outside the peripheral edge of the substrate 104. On the other hand, the beam monitor 106 is advantageous in that the ion beam 102 can be measured even when the ion beam 102 is in the center of the substrate 104.

  As shown in FIGS. 9 and 10, the beam monitor 106 irradiates the ion beam 102 with the measurement beam 130 along a scanning plane determined by the scanning direction of the ion beam 102 and the traveling direction of the ion beam 102. It is not always required that the irradiation direction of the measurement beam 130 be accurately along the scanning plane. The path of the measurement beam 130 may be determined so as to cross the scanning range 138 of the ion beam 102. As shown, the measurement beam 130 emitted from the measurement beam source 134 is linearly incident on the measurement beam detector 136. In this way, the ion beam 102 can be continuously monitored regardless of the scanning position of the ion beam 102.

  On the other hand, the reference beam 132 is branched from the measurement beam 130 by the beam optical system 135 to the outside of the scanning surface of the ion beam 102 and travels in a plane parallel to the scanning surface, and the measurement beam detector 136 does not pass through the ion beam 102. Incident to. In order to split the reference beam 132 from the measurement beam 130 before the scanning range 138 of the ion beam 102, the beam optical system 135 is an ion beam that is the end of the measurement beam source 134 and the ion beam scanning range 138 in the ion beam scanning direction. It is provided between the detector 122.

  The ion implantation apparatus 100 is not limited to the hybrid scan method. For example, the ion implantation apparatus 100 may employ a scanning method in which a so-called ribbon beam extending in a uniaxial direction and a mechanical scan in the orthogonal direction are combined. Alternatively, the ion implantation apparatus 100 may adopt a method of performing two-dimensional mechanical scanning in a plane perpendicular to the beam traveling direction with respect to the spot beam. The beam monitor 106 can be applied to any scanning method.

  FIG. 11 is a view showing a modification of the beam monitor 106 according to the second embodiment. The beam monitor 106 may include a plurality of measurement beam sources 134 and a plurality of measurement beam detectors 136. The plurality of measurement beam sources 134 are arranged along the longitudinal direction of the ion beam irradiation area 139. The ion beam irradiation area 139 is an area corresponding to a beam cross section of a ribbon-like ion beam, for example. The plurality of measurement beam detectors 136 are arranged along the longitudinal direction of the ion beam irradiation area 139 so as to face the plurality of measurement beam sources 134 with the ion beam irradiation area 139 interposed therebetween. Each of the plurality of measurement beam detectors 136 is arranged at a position to receive the measurement beam 130 from the corresponding measurement beam source 134. Accordingly, a plurality of measurement beams 130 intersecting the ion beam irradiation area 139 are arranged along the longitudinal direction of the ion beam irradiation area 139.

  The beam monitor 106 irradiates the measurement beam 130 to a plurality of positions in the ion beam irradiation area 139. The plurality of irradiation positions are arranged in the longitudinal direction of the ion beam irradiation area 139. Each irradiation position is irradiated with the measurement beam 130 from each of the plurality of measurement beam sources 134. The beam monitor 106 detects the measurement beams 130 irradiated to the plurality of positions by the plurality of measurement beam detectors 136. Each of the plurality of measurement beam detectors 136 outputs a detection signal S1 to the control system 128. In this way, the longitudinal distribution of the ion beam in the ion beam irradiation area 139 can be obtained.

  The plurality of measurement beams 130 are spot-like measurement beams in the illustrated example, but are not limited thereto, and are ribbon-like or long measurement beams having a width corresponding to the length of the ion beam irradiation area 139 in the longitudinal direction. There may be. Correspondingly, instead of a plurality of measurement beam detectors 136 separated from each other, a one-dimensional detector array having a detection region including a ribbon-like or long measurement beam may be provided.

  Further, the measurement target is not limited to the ribbon-shaped ion beam, and the configuration of the beam monitor 106 shown in FIG. 11 may be employed for measuring a spot beam that scans the ion beam irradiation area 139. The plurality of measurement beam sources 134 and the plurality of measurement beam detectors 136 may be measurement beam sources 134 and measurement beam detectors 136 that are movable along the longitudinal direction of the ion beam irradiation area 139. In this case, the movable measurement beam source 134 and the measurement beam detector 136 may be moved in synchronization with the scanning of the spot beam so as to continue the intersection of the measurement beam 130 and the spot beam.

  The beam monitor 106 illustrated in FIG. 11 may be provided in the ion implantation apparatus 100 illustrated in FIG. 9 instead of the beam monitor 106 illustrated in FIGS. 9 and 10. Alternatively, a beam monitor 106 obtained by combining the configurations shown in FIGS. 10 and 11 may be provided in the ion implantation apparatus 100. That is, the beam monitor 106 includes a plurality of measurement beam sources 134 and a plurality of measurement beam detectors 136 provided along the longitudinal direction of the ion beam irradiation area 139, and further, the longitudinal direction of the ion beam irradiation area 139. A measurement beam system having a beam path along

  The ion implantation apparatus 100 shown in FIGS. 9 and 10 is configured as a so-called single wafer type. That is, the ion implantation apparatus 100 is a type in which one substrate 104 is held at a time on the substrate support portion 124 and ion implantation processing is performed one by one. Note that the processing is not necessarily limited to processing one by one, and the substrate support unit 124 may be configured to provide two or more sheets simultaneously and provide mechanical scanning in at least one direction. Further, the ion implantation apparatus 100 may be configured as a so-called batch type in which a large number of substrates are placed on a rotatable table and rotated while simultaneously performing ion implantation on the large number of substrates.

  As shown in FIG. 9, the ion implantation apparatus 100 includes an ion source 108, a beam line assembly 110, and a vacuum exhaust system 126 for keeping the processing chamber 112 in a desired vacuum environment for the ion implantation process. The evacuation system 126 includes, for example, a high vacuum pump such as a cryopump and a roughing pump for roughing up to an operating pressure of the high vacuum pump.

  In addition, the ion implantation apparatus 100 includes a control system 128 for controlling the ion source 108, the mass analyzer 114, the beam transport system 116, the substrate support unit 124, and the evacuation system 126 to execute the ion implantation process, for example. . The control system 128 includes an ion implantation apparatus according to input signals from the beam measurement system including the detection signal S1, the reference signal S2, and the beam current signal S3, various data stored in the memory, input commands from the operator, and the like. 100 is controlled centrally. The control system 128 may be a dedicated controller for the beam monitor 106.

  The control system 128 includes, for example, arbitrary hardware including a CPU that executes various arithmetic processes, a ROM that stores various control programs, a RAM that is used as a work area for data storage and program execution, and various calculations or controls. And software such as a program for executing. The control system 128 may include input means such as a mouse and a keyboard for receiving input from an operator, communication means for communicating with other devices, and output means such as a display and a printer.

  The control system 128 may include a beam scan control unit 140 for controlling the beam scan, a mechanical scan control unit 142 for controlling the mechanical scan, and an ion beam monitor calculation unit 144. At least one element (for example, the ion beam monitor calculation unit 144) of the beam scan control unit 140, the mechanical scan control unit 142, and the ion beam monitor calculation unit 144 may constitute a control unit separate from the other elements. . The beam scan control unit 140, the mechanical scan control unit 142, and the ion beam monitor calculation unit 144 are realized by any computer CPU, memory, other hardware such as LSI, or software such as a program loaded in the memory. Indicates the function block to be executed. Those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  The ion beam monitor calculation unit 144 calculates a beam monitor output based on input signals from the beam measurement system including the detection signal S1, the reference signal S2, and the beam current signal S3. The beam monitor output is, for example, a beam current of the ion beam 102 or a dose amount injected into the substrate 104. The control system 128 stores the beam monitor output from the ion beam monitor calculation unit 144. Alternatively, the control system 128 may use the beam monitor output or may output it to the outside as required.

  The control system 128 may determine whether or not the ion beam 102 has changed during the ion implantation process on the substrate 104 based on the beam monitor output. Based on the determination result, the control system 128 may output a warning regarding the ion implantation process to the substrate 104. Alternatively, the control system 128 may specify the beam irradiation position where the beam current of the ion beam 102 or the dose injected into the substrate 104 varies based on the beam monitor output.

  The ion implantation process includes a relative movement between the ion beam 102 and the substrate 104 in a direction perpendicular to the traveling direction of the ion beam 102 incident on the processing chamber 112. This relative movement includes scanning of at least one of the ion beam 102 and the substrate 104 as described above. Thus, for example, the control system 128 controls the beam scan of the ion beam 102 and the mechanical scan of the substrate 104 according to a given scan sequence by operating the beam scan control unit 140 and the mechanical scan control unit 142 in a coordinated manner. To do. In this manner, the ion beam 102 can be irradiated over an ion beam irradiation region generally wider than the ion beam cross section.

  Here, the scanning sequence refers to a procedure for scanning the entire surface of the substrate 104 or an ion beam irradiation region that is a part thereof with the ion beam 102. The scanning sequence may be provided by direct input to the control system 128 by the operator, or may be set by the control system 128 to implement a given ion implantation process.

  FIG. 12 is a diagram for explaining an example of the scanning sequence 150 according to the second embodiment. As will be described in detail below, this scanning sequence 150 represents a scanning method suitable for the single-wafer type ion implantation apparatus 100 that does not essentially need to irradiate the ion beam 102 outside the substrate 104. For example, in the case of the hybrid scan method, scanning in one direction (for example, the x direction) in the scanning sequence 150 is performed by moving the substrate 104 with respect to the ion beam 102, and scanning in the other direction (for example, the y direction) is performed on the ion beam 102. This is done by beam scanning.

  The scanning sequence 150 starts from the scanning start position 152 and ends at the scanning end position 154. By executing the scan sequence 150 from the scan start position 152 to the scan end position 154 by the control system 128, an ion implantation region on the substrate 104 (for example, the entire region of the substrate 104 or the region excluding the peripheral portion of the substrate 104). The ion beam irradiation to the whole or a part thereof is completed. In one embodiment, the control system 128 may execute, for example, a serpentine scan sequence 150 that is configured such that the ion beam irradiation region occupies the contour or boundary of the ion implantation region on the substrate 104. During execution of the scanning sequence 150, the ion beam 102 is preferably monitored continuously or intermittently by the beam monitor 106.

  The scan sequence 150 typically includes at least one scan movement in a first direction and at least one scan movement in a second direction, which is perpendicular to the first scan movement. Normally, as shown in the drawing, the scanning sequence 150 includes a plurality of scanning movements in the first direction and a plurality of scanning movements in the second direction, and the scanning movement in the first direction and the second direction. Alternate scanning movement. As a result, a meandering scanning path from the scanning start position 152 to the scanning end position 154 results. In the case of the hybrid scan, the beam scan in the first direction and the mechanical scan in the second direction are alternately repeated.

  In one embodiment, the control system 128 may change the scan range due to the beam scan of the ion beam 102 during the mechanical scan of the substrate 104. That is, the scanning range by a certain beam scan may be different from the scanning range by the next beam scan after the subsequent mechanical scan. For example, the scanning range of each beam scan may be set based on the width of the ion implantation region on the substrate 104 in the scanning direction. An example of the scanning sequence 150 determined in this way is shown in FIG. In addition, for easy control, the scanning range of the beam scan may be set to a fixed value based on the maximum width in the scanning direction of the ion implantation region on the substrate 104 (for example, the diameter in the case of a circular substrate).

  For comparison, FIG. 12 shows an ion beam irradiation region 160 in a typical ion implantation process. The irradiation area 160 is a rectangular area. As shown in the drawing, it is understood that the ion beam is irradiated over a considerably wide range as compared with the substrate 104 (that is, compared with the region occupied by the scanning sequence 150). The outside of the substrate 104 is an area that does not need to be irradiated with an ion beam for the original purpose of ion implantation. In a typical configuration, these areas are also irradiated because the beam scan length is constrained and fixed by the Faraday cup placement in order to measure the beam current with the Faraday cup in each beam scan. .

  Therefore, according to the scanning sequence 150 according to the second embodiment, a region that does not necessarily require ion implantation can be minimized. Preferably, the ion beam irradiation region can be made to coincide with the ion implantation region. Since the total scanning distance of the scanning sequence 150 can be shortened, the throughput of the ion implantation process can be improved. Irradiation to the ion implantation unnecessary region is minimized and consumption of the ion material is also suppressed.

  The scan sequence 150 may include a first scan in which the ion beam 102 passes through the ion beam detector 122 and a second scan in which the ion beam 102 scans the substrate 104 without passing through the ion beam detector 122. . In FIG. 12, an example of the first scan is indicated by a broken line, and an example of the second scan is indicated by a solid line. The first scan may include at least one of a beam scan and a mechanical scan, or both. The second scan may also include at least one of a beam scan and a mechanical scan, or both, as described above.

  Therefore, the scanning sequence 150 includes, for example, a relatively long-distance beam scan 156 that includes the ion beam detector 122 in the scanning range, and a relatively short-distance beam scan 158 that does not include the ion beam detector 122 in the scanning range. And may be included. The long beam scan 156 has a scanning distance determined to include the ion implantation region on the substrate 104 and the ion beam detector 122 in the scanning range, and the short beam scan 158 has only the ion implantation region on the substrate 104 in the scanning range. The scanning distance may be determined so as to include it. The scanning sequence 150 may include a long beam scan 156 at least once. In this way, the ion implantation process can be performed while monitoring the ion beam 102 by using the beam monitor 106 and the ion beam detector 122 together.

  In another embodiment, similarly to the scanning sequence 150, the control system 128 may change the beam width of the ribbon-like ion beam according to the position where the substrate is irradiated.

  In a further embodiment, the control system 128 may determine the position where the intensity of the ion beam 102 has changed based on the relative position information between the ion beam 102 and the substrate 104 and the output of the beam monitor 106. Good. The control system 128 may identify the beam scan position from which the beam monitor output is obtained by associating the beam scan position information at a certain point of time with the beam monitor output at that point of time. The control system 128 may identify the mechanical scan position from which the beam monitor output is obtained by associating the mechanical scan position information at a certain point of time with the beam monitor output at that point of time. By integrating the beam scan position information and the mechanical scan position information obtained in this way, the control system 128 may specify the ion beam irradiation position on the substrate 104 corresponding to the beam monitor output. In this way, the ion beam irradiation position where the ion beam 102 has changed can be obtained.

  In the above, this invention was demonstrated based on the Example. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, various modifications are possible, and such modifications are within the scope of the present invention. By the way.

  The optical element related to the ion beam measurement apparatus 10 may be contaminated by contaminant particles such as ions contained in the ion beam and outgas from a substance irradiated with the ion beam. Contamination may deteriorate the optical characteristics of the optical element, such as transmittance or reflectance, and affect measurement.

  Therefore, the ion beam measurement apparatus 10 may include a protection unit for protecting the optical element from contamination. The protection means may be configured to exert an electrical repulsive force on the contaminating particles and prevent access of the contaminating particles to the optical element to be protected. Further, the protection means may be configured to adsorb the contaminant particles by applying an electrical attractive force to the contaminant particles. The protection means may include a physical barrier disposed in the vicinity of the optical element to be protected.

  FIG. 13 is a diagram illustrating an example of a protection device 70 for an optical element related to the ion beam measurement apparatus 10 according to an embodiment. Here, the 1st bending mirror 36 is mentioned as an example of the optical element which should be protected. The protection device 70 includes a bias power source 72 for applying a potential to the first bending mirror 36. The potential applied to the first folding mirror 36 is set so that an electrical repulsive force acts on the contaminant particles around the first folding mirror 36. For example, the bias power supply 72 applies a positive potential to the first folding mirror 36 in order to prevent access of positive ions to the first folding mirror 36. In this way, the approach of contaminating particles having the same electric charge as the potential applied to the first folding mirror 36 is prevented, and the adhesion of the contaminating particles to the first folding mirror 36 is suppressed. A decrease in reflectivity on the mirror surface can be suppressed.

  The protection device 70 includes a cylindrical member 74 that surrounds the first bending mirror 36. The cylindrical member 74 is provided along the path of the measurement beam 12 passing through the first bending mirror 36. Since the first bending mirror 36 is an optical element that bends the measurement beam 12 vertically, the cylindrical member 74 is similarly formed as a pipe line having a vertical bent portion. A first folding mirror 36 is accommodated in the bent portion. In this way, the cylindrical member 74 defines a region near the first folding mirror 36. The cylindrical member 74 can also be regarded as a physical barrier against contaminating particles disposed in the vicinity of the first folding mirror 36.

  The cylindrical member 74 includes an entrance portion 76 for entering the measurement beam 12 to the first folding mirror 36 and an exit portion 78 for emitting the measurement beam 12 from the first folding mirror 36. The inlet portion 76 and the outlet portion 78 are configured to be transmissive to the measurement beam 12. For example, the inlet portion 76 and the outlet portion 78 may be physically open or may be closed by a transparent member that is transparent to the measurement beam 12. Hereinafter, for convenience of explanation, the inlet portion 76 and the outlet portion 78 may be collectively referred to as a transmissive portion 76. The tubular member 74 includes at least one transmissive portion 76.

  The protection device 70 includes a protection member 80 for preventing contamination particles from entering the inside of the cylindrical member 74, and a bias power source 82 for applying a potential to the protection member 80. The protective member 80 is provided on the transmissive portion 76 (eg, the inlet portion 76, the outlet portion 78, or both the inlet portion 76 and the outlet portion 78). The protection member 80 occupies at least a part of a cross section that intersects the measurement beam 12 in the transmission portion 76. A cylindrical member 74 is provided as a support member for supporting the protection member 80.

  The protection member 80 is, for example, a wire mesh provided in the transmission portion 76. As an alternative, the protective member 80 may be a transparent member including a transparent conductive film. A bias power source 82 is connected to the metal mesh or the transparent conductive film of the protective member 80 so as to apply a potential.

  The potential applied to the protective member 80 by the bias power source 82 is set so that an electrical attractive force acts on the contaminating particles. For example, the bias power supply 82 applies a negative potential to the protective member 80 in order to attract positive ions to the protective member 80. Thus, the contaminating particles having a charge opposite to the potential applied to the protective member 80 are adsorbed by the protective member 80, and the contaminant particles enter the cylindrical member 74 and adhere to the first bending mirror 36. It is suppressed.

  As an alternative, the potential applied to the protective member 80 by the bias power source 82 may be set to cause an electrical repulsive force to act on contaminant particles approaching the protective member 80. For example, the bias power supply 82 applies a positive potential to the protective member 80 in order to prevent the cations from approaching the protective member 80. In this way, the contamination particles having the same electric potential as the potential applied to the protection member 80 are prevented from approaching the protection member 80, so that the contamination particles enter the cylindrical member 74 and the contamination particles enter the first folding mirror 36. Adhesion is suppressed.

  FIG. 14 is a diagram illustrating another example of the protection device 70 for the optical element related to the ion beam measurement apparatus 10 according to the embodiment. As an example of the optical element to be protected, the first bending mirror 36 is given as in the example shown in FIG. The protection device 70 includes at least one protection member 80 in the cylindrical member 74.

  The protection member 80 is a metal plate provided in the vicinity of the first bending mirror 36. The protection member 80 is provided at a location off the path of the measurement beam 12. In the illustrated example, two protection members 80 are provided, one protection member 80 extends from the entrance portion 76 toward the first folding mirror 36, and another protection member 80 extends from the exit portion 78. It extends toward the first folding mirror 36.

  The potential applied to the protective member 80 by the bias power source 82 is set so that an electrical attractive force acts on the contaminating particles. For example, the bias power supply 82 applies a negative potential to the protective member 80 in order to attract positive ions to the protective member 80. In this way, contaminant particles having a charge opposite to the potential applied to the protection member 80 are adsorbed by the protection member 80. The protective member 80 suppresses the contamination particles that have entered the cylindrical member 74 from adhering to the first folding mirror 36.

  The protective device 70 may include an ionization mechanism 84 for ionizing electrically neutral contaminant particles. The ionization mechanism 84 is, for example, a known ionization mechanism having a filament for ionizing a gas. The ionization mechanism 84 is provided in the vicinity of the inlet portion 76 or the outlet portion 78 of the cylindrical member 74. By electrically ionizing electrically neutral contaminant particles by the ionization mechanism 84, the electrical attractive force or repulsive force of the protective member 80 can be applied to such neutral contaminant particles.

  Since the protection device 70 includes the bias power source 72, the cylindrical member 74, and the protection member 80, the first folding mirror 36 can be well protected from contamination. On the other hand, when it is desired to further simplify the configuration of the protection device 70, the protection device 70 may not include any one of the bias power source 72, the cylindrical member 74, and the protection member 80. For example, when the protection device 70 includes the bias power source 72, the protection device 70 does not necessarily include the cylindrical member 74 and the protection member 80. When the protection device 70 includes the cylindrical member 74, the protection device 70 does not necessarily include either the bias power source 72 or the protection member 80.

  The optical element to be protected by the protection device 70 is not limited to the first bending mirror 36 illustrated in FIGS. 13 and 14. The protective device 70 may similarly protect any optical element for the measurement beam 12 or the reference beam 30. The optical element to be protected may be any optical element provided in the irradiation chamber 18 for irradiating the ion beam 14 with the measurement beam 12. Alternatively, any optical element provided in the vicinity of the path of the ion beam 14 may be used.

  Therefore, the protection device 70 may protect at least one of the beam splitter 32, the first folding mirror 36, the second folding mirror 38, and the third folding mirror 40, for example. When the optical system for the measurement beam 12 or the reference beam 30 includes a lens, the protection device 70 may protect the lens. Further, the protection device 70 may protect the window provided on the wall surface of the irradiation chamber 18. The window portion may be a window for allowing the measurement beam 12 or the reference beam 30 to enter the irradiation chamber 18 from the outside to the inside, or the measurement beam 12 or the reference beam 30 from the inside of the irradiation chamber 18 to the outside. It may be a window for emitting light. The window part may be a window for observing the inside of the irradiation chamber 18 from the outside.

  A particle beam therapy apparatus including an ion beam measurement apparatus according to an embodiment of the present invention may be provided. The particle beam therapy system may include a treatment room for accommodating an irradiation object to be irradiated with an ion beam, or a support base for supporting the irradiation object with respect to the ion beam. The particle beam therapy apparatus may include a control system for controlling the irradiation process of the ion beam to the irradiation object. The irradiation process may include controlling ion beam irradiation (or irradiation position) on the irradiation object. The particle beam therapy system irradiates the ion beam with a measurement beam that interacts with the ion beam, and detects the measurement beam irradiated to the ion beam, thereby providing an output related to the ion beam to the control system. A beam monitor may be provided. In one embodiment, the particle beam therapy device may be a proton beam therapy device and the ion beam may be a proton beam.

  In addition, a particle beam therapy system according to an embodiment of the present invention includes a measurement beam source for emitting a measurement beam that generates an interaction with an ion beam, and a measurement emitted from the measurement beam source and applied to the ion beam. An ion beam measurement device including a measurement beam detector for detecting a beam may be provided. Various embodiments and modifications described in relation to the ion beam measurement apparatus 10 and the ion implantation apparatus 100 described above may be applied to an ion beam measurement apparatus and a particle beam therapy apparatus for a particle beam therapy apparatus. . In that case, “object to be processed” may be read as “object to be irradiated”.

  10 ion beam measurement device, 12 measurement beam, 14 ion beam, 20 measurement beam source, 22 measurement beam detector, 24 beam optical system, 70 protection device, 100 ion implantation device, 102 ion beam, 104 substrate, 106 beam monitor, 112 processing chamber, 122 ion beam detector, 128 control system, 130 measuring beam, 134 measuring beam source, 150 scanning sequence.

Claims (15)

A control system for controlling the ion implantation process by the ion beam to the workpiece;
Irradiating the ion beam with a measurement beam that interacts with the ion beam, and detecting the measurement beam applied to the ion beam, thereby providing an output related to the ion beam to the control system An ion implantation apparatus comprising a beam monitor.   The ion implantation apparatus according to claim 1, wherein the beam monitor irradiates the ion beam with the measurement beam so that the measurement beam crosses a passing region of the ion beam by scanning. An ion beam detector for receiving the ion beam and measuring the ion beam;
The control system includes a first scan in which the ion beam passes through the ion beam detector, and a second scan in which the ion beam scans an object to be processed without passing through the ion beam detector. The ion implantation apparatus according to claim 1, wherein a sequence is executed.   4. The ion implantation apparatus according to claim 1, wherein the control system allows a change in a scanning range of the ion beam during mechanical scanning of the workpiece. 5.   The control system identifies a position where the ion beam fluctuates based on relative position information between the ion beam and the object to be processed and an output of the beam monitor. The ion implantation apparatus in any one of. The ion beam is an ion beam having a cross-sectional shape extending in the longitudinal direction;
The beam monitor irradiates the measurement beam to a plurality of positions in the longitudinal direction of the ion beam, and detects the measurement beam irradiated to the plurality of positions, thereby controlling the longitudinal distribution of the ion beam. The ion implantation apparatus according to claim 1, wherein the ion implantation apparatus is provided in a system. A measurement beam source for emitting a measurement beam that interacts with the ion beam;
An ion beam measurement apparatus comprising: a measurement beam detector for detecting a measurement beam emitted from the measurement beam source and applied to the ion beam. The interaction between the ion beam and the measurement beam includes at least one of absorption, diffraction, scattering, reflection, and transmission of the measurement beam by the ion beam,
The ion beam measurement apparatus according to claim 7, wherein the measurement beam detector outputs a detection signal related to the intensity of the measurement beam irradiated to the ion beam.   9. The measurement beam source includes a laser light source that emits a laser beam having a wavelength that matches an absorption wavelength of an ion species included in an ion beam or a wavelength region that includes the absorption wavelength. Ion beam measuring device. A beam optical system for splitting a reference beam emitted from the measurement beam source and not irradiated on the ion beam from the measurement beam between the measurement beam source and the ion beam irradiation position of the measurement beam;
The ion beam measurement apparatus according to claim 7, further comprising a reference beam detector for detecting the reference beam.   The measurement beam detector is provided outside the irradiation chamber for irradiating the ion beam with the measurement beam, and the irradiation chamber and the measurement beam detector are connected by a light guide member for transmitting the measurement beam. The ion beam measurement apparatus according to claim 7, wherein the ion beam measurement apparatus is provided.   9. The ion beam measurement apparatus according to claim 7, wherein the measurement beam source includes an electromagnetic wave source that emits an electromagnetic wave having directivity that reflects or transmits in accordance with a plasma frequency of the ion beam.   The protective means for protecting the optical element for the said measurement beam provided in the irradiation chamber for irradiating an ion beam with a measurement beam from contamination is characterized by the above-mentioned. The ion beam measuring apparatus described.   An ion beam irradiation apparatus comprising the ion beam measurement apparatus according to claim 7. Irradiating the ion beam with a measurement beam that interacts with the ion beam;
Detecting the measurement beam irradiated to the ion beam. A method for measuring an ion beam, comprising:

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